－Bob, have you packed yet?

－Yes, Mum.

－Look over and       that you have taken everything you need.

A．look for

B．make sure

C．find out

D．work out

慢性化脓性骨髓炎瘘管经久不愈的原因是（）

A.骨质增生

B.脓腔或死骨存在

C.骨干增粗

D.新生骨形成

E.骨髓腔闭塞